1. Field of the Invention
The present invention relates to a sewing machine having a thread cutting device for severing the free end of the needle thread at the beginning of a sewing operation.
2. Description of the Prior Art
In a conventional sewing machine having a thread cutting device a needle thread and a bobbin thread are severed simultaneously below the throat plate upon completion of a sewing operation. Subsequent to the severing operation the needle and presser foot are both raised to their uppermost positions allowing the workpiece to be withdrawn. The withdrawal of the workpiece will place the free end of the needle thread which extends through the needle eye upon the upper surface of the throat plate.
If the sewing machine is not equipped with a suitable wiper device the free end of the needle thread will be disposed on the upper surface of a subsequent workpiece which is positioned beneath the presser foot and needle and will be held in place thereon during a subsequent sewing operation by means of the presser foot. Thus the free end of the needle thread will be flexibly extended from the upper surface of the workpiece upon completion of a subsequent sewing operation. On the other hand, if the sewing machine is equipped with a wiper device, the free end of the needle thread will be moved aside so as to be offset relative to the presser foot and will be drawn downwardly through the workpiece during the first penetration of the needle in a succeeding sewing operation. The free end of the needle thread below the throat plate is apt to become entangled during the succeeding sewing operation so that the reverse side of the workpiece will be unsightly upon withdrawal of the workpiece after completion of the sewing operation. In order to obviate the foregoing difficulties with the free end of the needle thread it has been necessary to cut off the free end of the needle thread manually so that the workpiece will be neat and attractive.